Spectroscopic classification of three supernovae at Asiago

ATel #4989; L. Tomasella, S. Benetti, A. Pastorello, E. Cappellaro, M. Turatto, P. Ochner (Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica)
on 18 Apr 2013; 10:25 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Stefano Benetti (stefano.benetti@oapd.inaf.it)

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We report the spectroscopic confirmation of three supernovae with observations obtained with the 1.82-m Copernico Telescope in Asiago (+ AFOSC; range 340-820 nm, resolution 1.3 nm).

A spectrum of PSN J10482657+3824079 obtained on Apr 17.94 UT shows that this is a young type-II supernova. The spectrum is dominated by a blue continuum with a black-body temperature of about 10800 K. Emission Balmer and He I 587.6-nm lines are recovered at the recession velocity of the host galaxy, v = 7661 km/s (from SDSS data release 5, 2006 via NED).

A spectrogram of CSS130415:114802+543439 obtained on Apr. 18.10 UT suggests that this is a type-Ic hypernova very similar to SN 1998bw at about 10 days after maximum light. The redshift of the host galaxy is about 0.0545 as measured from narrow Halpha, [O III] and Hbeta interstellar emission lines.

A spectrum of CSS130415:131729+424430 shows that this is a type-Ia supernova at redshift z~0.036. The best match was found with various type-Ia supernovae about one week after the maximum light. The expansion velocity as deduced from the position of the Si-II 635.5nm absorption is about 10100 km/s.

The Asiago classification spectra are posted at this website: URL http://graspa.oapd.inaf.it ; classification was made via GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383) and SNID (Blondin and Tonry 2007, Ap.J. 666, 1024).